Dough mixer



Aug. 27,1929.

F. x. LAUTERBUR Er A1.' 1,72 6,033

noUGH 'Inu-:n Filed Aug. V25. 1926 2 Sheets-Sheet 1' Nmdm l Nnnunmu IIMMHIUUL THUN HHHUJH l -m y XoINVENTOR.

A By m ATTORNEY.

F. X. LAUTERBUR ET AL n DoUGH MIXER Filed Aug. 25, 1926 2 sheets-sheet I N VENTOR.

Patented Aug. 27, 1929.

PATENT ori-"ics,

FRANK x. LAUTERBUR AND EDWARD mmAurnnm'm, or SIDNEY, omo.

DOUGH Application iled August 25,1926. Serial No. 131,478'.

Our invention relates to machines for mixlng dough in preparation for the making yof bread and other products, and has as itsV prime object the thorough incorporation and working of batches of dough so as tocause the proper development of gluten, at the minimum of mixing time, and with theminimum of heat of friction produced inA the mass. p.

The type of mixer employed by us is preferably the standard dough mixer bowl having a curved bottom and straight ends and, sides, within which bowl the vmixer blades are caused to revolve about an axis which is preferablyl at substantially theJ center of curvature of the base 'of the bowl. y

The aim of our structure is to accomplish a very thorough mixing of the dough, while keeping'it away from j the ends, sides and y bottom of the bowl, thus eliminating rub-v hing and consequent heat, and' permitting a rapid movement of the bladeswithout danger to the batch, and to accomplish this with mixing blades which are evenly balanced so that there is a minimum of strain.

on the operating parts, and so that vibration of the mechanism is reduced to a minimum. Considering the in redients: as restingin the'bottom of the mixing bowl, our strucing bars results in working the dough in and out alternately to the maximum degree at the central cross vertical 'plane of the bowl, and intermediate these two workings vforcing the dough inwardly from the ends of the bowl by means of blades which also cause a spinning action on the dough that is most rapid at the outside of the batch. With mixing bars operating in this manner, anda retarder to constriet the dough mass ing which is effective in the highest degree` with the minimum of deleterious results. Thus, as atypical test, we can dump apound of lamp black into a full sized bakers mixer filled with'a normal dough batch, and completely blacken all parts of the batch within.

'one minute of mixing time lby the use of our invention, without the development nf excess ture, arrangement and operation of the mixmode of operation of the device.

and hold it back at the point of entrance of the blades into the mass, together with a.

as alternately bent from the ends inwardly 65 and outwardly toward the axis of the mixing element, and in radial planes passing through the axis, and the thirdblade is bent from the ends toward the middle in a plane tangential to the path of rotation, with the bendpointing away from, the direction of rotation.

We are aware that the art is full of various kinds of mixing agitators, but know of none, in which thel mode of operation is similar to that of our mechanism, such as is briefly above outlined, or in which the various problems which severely limit the possible manipulations of a Vdo'ugli batch are s0 effectively provided for.

We accomplish our objects by that certain construction and arrangement of parts to be hereinafter more specifically pointed out and claimed.

In the drawings Figure l is an end view of the assembly.

`Figure 2 4is a side elevation of the assembly shown in Figure l. 'A

Figure 3 is a diagram illustrating the 9o Figure 4 is a lan view of the .preferred arrangement of lades.

Figure 5' is a vertical section taken along the line- 5*-,5 of Figure Figure 6 is a vertical section taken along 95 the line 6-.-6 of Figure 4.

f Generally indicated at l is the frame of the machine on which are mounted the usual actuating devices which cause the rotation of the agitator shaft of the machine. These 100 are not specifically described, as they form no art of our invention; The agitator bowl- 2 ias trunnions 3, which are pivotally mounted in the journals 4 in the machine frame. The bowl has`an open top, which `is covered by a cover plate 5, which is prefhas end spiders thereon within the bowl, which mount the agitating bars. The spider 'arms 7 and 7a, are of equal length and weight, and the third bar 7 b.is slightly shorter. The bars 7 are connected across the span of the shaft by means of curved agitator bar 9, which curves inwardly in substantially a plane that bisects the axis of the beater shaft. The bars 7a are connected by a like agitator bar 9, which, however, is set so that it curves outwardly in said plane. The bars 7b are connected by a like bar 9b, which extends in a curve away from the direction of motion of the beater shaft, in a plane tangential Ato the path of motion of the spiders.

When this special agitator is revolved, the action on a mass of dough is as graphically shown in Figure 3. Leaving out of consideration the effect of each bar churning the dough in a circular path, the bar 9 pushes in on the dough, the bar 9 pushes out on the dough, and the-bar 9", pushes the dough from the' ends of the bowl toward the middle.

The breaker bar 11 is mounted on brackets 12, which are disposed adjacent the ends of the bowl with bolts 13, which enable the brackets to pivot so as to carrythe breaker bar to a desired position with relation to the side wall of the mixer and the top level of the dough and path ofmovement of the agitator or beater bars.

In the base of the bowl, we mount a revtarding roll. In the particular type noted, there is a shaft l5 extending across the bowl on which is mounted a rotatable sleeve 14.

'In operation, the bowl is filled with a batch to be made into dough, and the blades are set into operation, with the lid closed over the bowl. The dough is vworked up and mixed with about the following actions taking place in addition to the imparting of circular or spinning motion. As each blade approaches the breaker bar, the dough is kept from being forced against the bowl wall, and tends to stay outside of the breaker bar. Thus there is compression of the dough at this point, but without the hurtful action of developing much friction against the vertical wall of the bowl. As each blade approaches the bar at the bottom of the bowl, the dough is again given an extra presv sure, but rolls over thebar without being pressed against the bottom of the bowl, thus developing hurtful friction.

The action of the bars due to their special ter, and finally inwardly from the ends of the bowl, parallel to the plane of the bowl wall toward the center. The two bars fixed to the bowl wall serve a distributing function of spreading the dough out, since they are parallel. y

The arms 9-and 9, balance each other, and the length of the arms 7", together with the bar 9b, brings the center'of gravity of this element of the` spider to substantially the same, as the other two bars and spider arms.

Thespider and beater bars are thus equally balanced, which rids the machine of vibratory tendency. Furthermore, the bars are the same in each case, so far as manufacturing them are concerned, and are set in place in the spider arms in a different manner to give theproper agitation.

The amount of heat developed by friction when the machine is operated rapidly is much smaller than any machine, having the general type illustrated, has ever shown to our knowledge. This permits a more rapid action, as-does the balance of the agitator.

The working in and out, greatest at the center of the mass, and in from the ends to the center, particularly when taken together with the several abutment bars in the bowl itself, results in the high degree of effectiveness which we find our machine to possess.

We do not insist upon a shape of bar which is identical with the form that we have illustrated, so long as the tendency of working is as described, resulting in a very perfect balance in the operation, and a minimum of wiping against the sides of the bowl to develop friction with a maximum of intermixture and agitation of all parts of the vIH 33S.

The retarding rolls or bars which serve kneading and 'stretching .functions in con-` nection with the agitatorl arms, lmust be of substantial size as distinguished from ribs or roughened portions in the bowl walls. Also it is required that at least for the upper bar, they be adjustable with relation to the 'bowl wall so as to control the spacing of the dough has developed far enough to begin to stretch and remain a coherent mass carried around with the agitator, the upper bar must provide that the mass is kept away from the inner wall of the bowl while being stretched and worked.

Without considerable size, the upper roll or bar could not serve these functions which are somewhat analogous to those of a shelf' with the agitator bars as an abutment against which individual working actions are initiated,`at each entrance of the agitator bar into the partiallyq suspended, accumulated and retarded mass.

The same requirements for size are present in the lower retarding rolls or bars, since the functions developed are quite similar to those of the upper roll. The dough mass spun worked and stretched away from the upper roll, stays practically clear of the bowl wall until it is again held up and worked and stretched so as to repeat the action above fully described for the upper roll. Thus the action of the lower roll is again such as will keep the dough mass Vaway from frictional contact with the bowl wall during its upward area of movement.

The lower roll as noted should have a rotary surface or be revolubly mounted, so that it will permit the dough mass to readily pass up over the top between the roll and the agitator device. This cuts down friction while at the same time keeping the dough away from the bowl walls, and imparting a lower zone of stretching similar to the upper zone.

It is of importance to consider our invention from the point of view of high speed mixing of dough more particularly, although it is not limited to this one aspect.

The operation of the machine at high speeds can be resorted to in the bakery without increase of temperature of the mass to such a degreeas would interfere with the action of the elements of fermentation. In other words the development of heat is insufiicient to result in overheating by the timethe batch is finished. Also there is a notable aeration of the dough and a much improved tough gluten development, and our machine has the opposite effect of the use of cleats or roughened elements in the base of the mixer bowl, since the elfect of the several stretcher or breaker bars is to cut down tearing action on the dough, keep it away from the bowl walls, and hold it in relation to the agitator bars in such a way that the dough is spun or stretched over the bars..

Tests have period is cut nearly one-third the usual time in the bakery by our new type machine? and less sugar and yeast foods are required. The gluten being tougher makes a better keeping loaf, and expands more in the baking, giving a larger loaf. The dough inside the loaves or crumb as it is called, is whiter because of the stretching without cutting and friction that is developed in our machine. There is no need for refrigeration or to use ice so far as the mixer is concerned, and the nature of the curved bars of the agitator is such, as in yco-operation with the stretching, and retarding and bowl clearing rolls, as to give a greater agitation per unit of mixing time than has ever been accomplished in our experience.v

The machine is easy to clean because the agitator bars do not come close to the bowl walls and the balance of the agitator, and effect of the top stretching and retarding roll to cut down sla of the 'dough massagainst the bowl wa l due to centrifugal force, results in a machine with hardly any appreciable period of vibration-when working or idle.

Having thus described our invention, what we claim as new and desire to secure by Letters Patent is 1. In a dough mixer, an agitating element formed bymeans of rotated spiders connected across the bowl with arms, said arms being bent alternatel so that the middle of one projects towar the agitator axis of rotation, the middle of another projects away from the agitator axis of rotation, and

the third projects substantially tangential to shown that fermentation -yv its path, and at its middle extends away from the direction of rotation.

2. In a dough mixer, a revolving mixer formed, of spider arms, and blades connecting them across thev bowl, said blades being bowed, one counter to the direction of the axis of the mixer to force the dough in toward the middle of'the bowl, one in the direction of the axis of the mixer to force it out from the middle of the bowl, and one counter to the direction of movement of said arms to force it inwardly from both ends of the bowl toward the middle.

3. In a dough mixer having a bowl, and a revolving mixer formed of spider arms, and blades connecting them across the bowl, said blades being bowed, one counter to the direction of the axis of the mixer to force the dough in toward the middle' of the bowl, one in the direction of the axis of the mixer to force it out from the middle of the bowl, and one counter to the direction of movement of said arms to force it inwardly from both ends of the bowl toward the middle,

and "a plurality of bars ixed with relation to the owl, and extending across the bowl to engage evenly across the mass.

4f. In a dough mixer, the combination with a bowl of an agitator therein, said agitatorhaving means for enforcing a circu- 'la'r movement on the vdough and amov'ement away from the Iends of the bowl, at

' @all times, a cross element held in the bowly ,adjacent the side thereof, said element during the operation of the mixer having a fixed axis and so located as to engage the ldough at -approximately the upper limit of thereof.

the path ofthe agitator within the bowl.

5.'In a dough mixer, the combination' with a bowl of anv agitator therein, said agitator hav/ing means for enforcing a circular movement on the dough and a movement away from the ends of the bowl, at all times, and an adjustable cross element held in the bowl adjacent the side thereof, and

located to engage the dough at approximatelyv 'the upper limit of the path ofthe agitator within the bowl.

6. In a dough mixer, the combination with a U-shaped bwl, and a rotary agita- -tortending to cause a circular movement' of dough in the bowl, of at least one breaker or stretching bar adj-ustably mounted in the bowl so as to extend across the interior at lapproximately the level which .agitator traverses at the upper limit of its movement' within the bowl.

'v7.-In a dough ymixer, the combination with a. U-'shaped bowl', and a rotary agitator tending to-cause a circular movement of dough in the bowl, of atleast one 'breakeri tending to cause a ,circular movement of dough-in the bowl, of at least one breaker bar adjustably mounted in the bowl so as toextend acrossthe interior at yapproximately the levelwhich the agitator traverses at the u per limit of its movement within the bowl 4and at least one retarding element within the bowl, locatedadjacent the base thereof, said retarding element having a rotatable body extending substantially in alignment with the axis of rotation thereof,

so as to give with the impulse of the dough against it in a rotary direction. 9, Ina dough mixer, the combination of 'a U shaped bowt, means to impart a movey ment circularly of the bowl, accompanied by a. lurality of movements other than circular yy of the bowl, to the dough held therein, and -constituting a rotary agitator,

and bars 'aboveand below the axis of the agitatorA opposing the tangential impulse of the circular `movement `imparted to the dough by the agitator.

10. In a dough lxer, the combination of, a U shaped bowl, means to impart a movement circularly of the bowl, accompanied by a plurality of movements other than circularly -of the bowl, to the dough held therein, and-constituting a rotary a itator, and means in they bowl opposing t ej tangential impulse of the circular move ment imparted to the dough by the agitator,

vsaid means being `located in the path of the larly of the bowl, to the dough held therein,

and yconstituting `a rotary agitator, and means Ain the' bowl opposing the tangential impulse ot.the` circular movement imparted to the doughfby the agitator, said means beingadjustable 1n its position with relation to the' bowl)Y wall, and located adjacent the line ofentry ofthe elements of the agitator into `.the doughv mass within the bowl from aboveuy x12. Ina dough mixer, the combination of a Ushaped'bOWI, means to impart amovement circularly of the bowl and movement othertthan circularly thereof, to the. dough held therein, and constituting a rotary agitator, and means in the bowl and adjustably spaced away from the sides thereof, located so as to engage the mass of dough across the bowl at a point where the elements enter they dough from above.

13. An agitator for mixer bowls, having end terminal members for mounting the agitator bars, at least three agitator bars set in said end terminal members, said bars being differently bowed sov that each traverses a different path through a mass being agitated thereby, and said terminal members and bars so proportioned and weighted thatv irrespective ofthepaths traversed, said members and bars are equally balanced with relation to the axis of the agitator, thus preventing vibration when said agitator is` revolved.

v 14. In a high'speed mixer, the combination of a bowl having a curved bottom and substantially straight sides, and a rotary agitator having bars extending across the bowl,

of elements within the bowl locatedat intervals in the path of the agitator, and of substantial size so as to delay the movement of the dough mass without lfrictionally retarding-it, said elements comprising at leastone axially revoluble' reta-rding roll having an outer periphery revoluble by engagement with the ingredients mixed withl the mixer and one breaker bar adjustably mounted so as to be adjustable to a desired osition with respect to a dough mass in sai mixer.

l5. In a dough mixer, the combination with a U shaped bowl, and an agitator having intersp'aced bars extending across the interior of the bowl, of at least one breaker bar adjustably mounted in the bowl so as to extend across the interior at approximate- 1y the level "which the bars of the agitator traverse at the upperlimit of their movement within the bowl, and at least one retarding element within the bowl, located adjacent the base thereof.

16. In a dough mixer, the combination with a U shaped bowl, and an agitator having interspaced bars extending across the interior o the bowl, of at least one breaker bar adjustably mounted in the bowl so as to extend across the interior at approximately the level which the bars of the agitator traverse at the .upper limit of their movement within the` bowl, and at least one re- 25 tarding element within the bowl,located adjacent the base thereof, said retarding elementhaving a rotatable body, so as tolgive c with the impulse of the dough against it in a rotary direction.

17. In a mixer, a tator therein tending to move the dough around within the bowl, and means for keep- U shaped bowl, an agi-v ing the dough away from the U shapedbowl walls during its movement under impulse of the agitator, said means comprising a revolvingroll element near the base of the bowl,

and a cross element spaced away from the bowl and so located as to vect as a shelf to `hold back the dough from being flung centrifugallyagainst the U shaped bowl wall.

18. In a mixer a bowl having a curved wall, an agitator formed of bars extending across the bowl, and moving in one direction of rotation within the bowl, and a plurality of stretching members located adjacent the bowl wall and formed at least in part of rotatable c lindrical members so as not to develop a fyriction against the dough and to lift dough which comes into` centrifugal contacts therewith away from the bowl wall.

FRANK X. LAUTERBUR. EDWARD J. LAUTERBUR. 

